Domestic pets, dogs and cats for example, chew as part of their play. A chewable toy or edible pet treat that is nutritious and also promotes good health, particularly good oral hygiene, is highly desirable. Additionally, there is a considerable population of domestic pets that are overweight. Thus, a chewable toy or edible pet treat that provides minimal or little starch when ingested is also desirable.
Conventional manufacturers of protein-based pet chews typically employ horizontal injection molding machines with purchase prices well above one hundred thousand dollars. Furthermore, horizontal injection machines are designed to operate under very high pressures, e.g., 50 to 500 tons per square inch are typical, with large injection quantities, or “shot sizes.” These characteristics enable non-pet related manufacturers to use such horizontal injection machines in the manufacture of an array of items, including large articles such as automobile parts, household and garden products. When using such horizontal injection molding machines, pet chew manufacturers typically employ a two-piece mold for their thermoplastic compositions which typically produce up to twelve articles per cycle. The mold for a horizontal injection molding machine is positioned vertically, or perpendicular, to the, typically linear, direction of injection, and accordingly must be bolted into place, due to gravity. After the molten, raw material has been injected into the mold, the machine operator is required to wait for the mold to cool, typically three to five minutes, before opening the mold and releasing the injection-molded articles, so that the mold may again be used. Thus, the entire cycle time of conventional pet chew toy manufacturing via a horizontal injection molding machine is approximately twelve (12) chew toys per six (6) minutes or 120 chew toys per hour. Improvements to this manufacturing process, are desirable and needed to increase the rate of article production, decrease the per article cost and reduce the required capital costs.
Conventional pet chew manufacturers, using horizontal injection molding machines, require the resulting products of extrusion, the extrudate, to be formed into pellets or beads, and to have a moisture content of about 15 to 25 wt. %. These products of extrusion, or extrudate, are then fed into the injection molding machines, with such moisture content, to enable a better flow of the molten material in the injection process. This, however, results in the creation of injection-molded chews or bones with a very high moisture content, which require one to five days of additional drying at a low temperature, to harden. An improved method yielding dried final articles in a shorter period of time also remains desirable and needed. The present invention, in its several embodiments, addresses these needs.